To obtain a flooring material for floor heating that can easily and surely conduct nailing fixation to a subfloor.

In a flooring material 1, where a recessed groove 11 for incorporating a heat generation source 20, such as pipe for hot water and an electric heater, is set as back side, a distance A from a side end 17 where tenon 13 is formed to a recessed groove 11A, and distance B from a side end 18, where a mortise 14 is formed to a recessed groove 11B are expressed as A>B (or A<B), and A+B=C (the distance between recessed grooves 11).